1. Field of Invention
The present invention relates to the detection of cracks and incomplete fusions in pipeline welds and, more particularly, to a screening process which utilizes pattern recognition to identify the location of cracks and incomplete fusions along a welded pipeline using transverse magnetic flux technology.
2. Description of Related Art
Pipelines with welded longitudinal-seams have experienced in-service failures due to incomplete fusion and hook cracks. These issues are well known, well understood, and have been serious considerations of pipeline integrity management groups throughout the industry for a number of years. They have also been one of the focus elements of the regulatory agencies responsible for assuring that pipeline operators are assessing all threats to the integrity of their pipelines.
In normal analysis processes utilizing transverse flux technology, detection processes have been primarily focused on the identification and quantification of volumetric metal loss anomalies along a pipeline. These algorithms utilize the amount of flux leakage detected, the length of anomaly and width of anomaly (number of channels) to determine depth. When a “metal-loss” sizing algorithm is applied to narrow axial anomalies, the resulting predicted depth can be considerably shallower than the actual depth. Because there are a limited number of channels affected by the anomalies, the calculated depth is low and most often below a minimum reporting threshold. This results in a non-reported anomaly, which could lead to pipeline failures. As such, recognized by Applicants is the need for a new identification process that overcomes such limitations.